Fluid pressure producing device



Sapt 21, 1937. J. R.-HEIDLOFF 2,093,557

FLUID PRESSURE PRODUCING DEVICE 1 Filed Feb. 20, 1936 F 2 INVENTOR.

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prove the structure of Patented Sept. 21, 1937 UNITED! STATES PATIENT OFFICE} 2.093.557 FLUID rnnssrmn monuome nsvrou Joseph R. Heidloii, Detroit, Mich, assignor to Hydraulic Brake Company, Detroit, Mich, a

corporation of California Application February 20, 1936, Serial No. 64.854

'1 Claims. on. eat-54.0)

' system in which the possibility of-overloading 1 the system is avoided.

, ing the friction elements of brakes. tors are arranged in pairs, one pair for actuating Other" objects of the invention will appear from the followingdescription taken in connection with the drawing forming a part of this.

specification, and in which,-

Fig. 1 is a schematic view of a fluid pressure brake system embodying the invention; and

Fig. 21s a vertical sectional View of the fluid pressure producing device of the system.

Referring to the drawing for more specific details of the invention, Ml represents a. fluid reservoir having'a. filling opening I2 which may be closed as by a plug I4 having openings i6 for venting the reservoir to the atmosphere. A cyl inder It at the base of the reservoir has a port 20 adjacent its forward end providing a com-- munication between the cylinder and the reservoir, and a head 22 threaded into the forward end of the cylinder has an axial bore providing a discharge port 24 for the cylinder. The head has a reducedsection providing in conjunction r with the wall of the cylinder an annular chamber 26 communicating with the reservoir III by way ofthe port 20, and a plurality of spaced ports 23 providing communications between the annular chamber 26 and the cylinder I8. I

A fluid pressure delivery pipe or conduit 36 suitably connected to the discharge port '24 has,

branches 32, 34, 36 and 38 connected respectively to fluid pressure actuated motors til for actuat- The morotatable drum 44 associated therewith, corre-' sponding friction elements or shoes 46 pivoted on the backing plate, and a motor such as the motor til mounted on the backing plate between also serves to return the piston to its retracted the shoes and operative to spread the shoes into engagement with the drum 44 against the resistance of a retractile spring 48.

A collapsible leak-proof cup 58 seated on'the head of the cylinder controls the ports 28. This cup has a concentric converging tube 52'extending into the discharge port 24, the purpose of which will hereinafter appear, and a. spring seat v54 slidable in the cylinder rests in the bottom of the cup. The spring seat has a concentric opening 58, registering. with the converging tube 10 52, and a plurality of spaced ports 58 in its wall, the purpose or which will also hereinafter ap pear. A detailed description of thelcollapsible leak-proof cup 5!! is omitted from the instant I application since the cup constitutes the subject matter of my application for United States Letters Patent, Serial No. 54,491, filed December 14, 1935.

A piston 60 reciprocable in the cylinder i8 is retained against displacement by a washer 62 suitably secured in the open end of the cylinder,

and seated on the head of the piston is a leakproof cup 64 providing against-seepage of fluid from the cylinder. A pin 66 reciprocable in the converging tube, and providing in conjunction therewith a control valve indicated generally at 68 for the discharge port, has a head 10pm vided. with a flange l2 normally seated on the leak-proof cup 64 on the head of the piston and cooperating therewith to provide a valve indicated generally at- M. A chamber I6 of the valve Id communicates with an axial passage 18 in the pin, and the pin has diametral passages 89 providing communications, when the appara- 35 tus is at rest, between the axial passage I8 in the pin 66 and the cylinder l8. A spring 82 interposed between the head it and the spring seat 56 urges the valves 68 and It to their seats and position.

The piston has a recess 8% in its back for the reception of one end of a thrust pin 86, on the other end of which is a coupling 88 connected by a flexible boot 99 to the open end of the cylinder for the exclusion of dust. moisture and other foreign substances. A red 92 connects the coupling 88 to a foot pedal lever 9 pivotally mounted as at 96 and connected by a retractile spring 93 to a flxed support Hit. 50

In operation, upon depressing the foot pedal lever 94, force is transmitted therefrom through the rod 92 and the thrust pin to the piston 60, resulting in moving the piston on its compression stroke. As the piston moves on its compression 5 stroke fluid is displaced from the cylinder l8 past the valve 68, thence through the discharge port 24 and fluid pressure delivery pipe 30 and its branches, into the fluid pressure actuated motors 40, causing actuation of the motors withthe resultant movement of the shoes 46 against the resistance of the retractile springs 48 into engagement with the drums 44. When the pressure in the system reaches a degree sufllciently high to eflectively actuate the brakes, the pin 66 has advanced suiflciently to place the diametral passages 80 in the pin in direct com munication with the system.

Upon release of the foot pedal lever by the operator of the vehicle, this lever is returned to its normal position under the influence of its retractile spring 98. This movement of the foot pedal lever retracts the rod 92 and the thrust pin 86, resulting in the release of the piston, whereupon the piston is free to be moved toward its're- I tracted position by the forces acting upon it.

Atthe moment the foot pedal lever is released, the space 16 between the piston 60 and valve 14 is in direct communication with the wheel cylby the action of this returning fluid in forcing the piston 60 to the left. This returning fluid continues to force the piston 60 to the left and the valve H under the action of its spring 82 closely follows the piston in its retractile movement.

When the valve 14 has moved such a distance toward the left that the passages 80 enter the converging tube 52 of the cup 50, these passages 80 are thereupon cut oiffrom communication with the wheel cylinders. The spring 82 then moves valve 14 into contact with cup 64 on the head of piston 60, and thereafter valve I4 and piston 60 move together toward the lef and thereby create vacuum in the cylinder which is satisfied by fluid from the reservoir which is drawn in past the cup 50. After the passages 80 have been cut oil from communication withthe wheel cylinders by the tube 52, any fluid returned by the wheel cylinders must lift the cup 50 from its seat and flow back into the reservoir through passages 28 and 20.

Although this invention has been described in connection with certain specific embodiments, the principles involved are susceptible of numerous other applications that will readily occur to persons skilled in the art. The invention is, therefore, to be limited only as indicated by the scope of the appended claims.

Having thus described the various features of the invention, what I claim as new and desire to secure by Letters Patent is,

trolling the ports, and a valve on the head of the piston operative to alternately communicate with the cylinder and the discharge port to control the creation of suction in said cylinder during the return stroke of said piston.

3. A fluid pressure producing-device comprising a cylinder having an inlet port and a discharge port, a piston reciprocable in the cylinder, a valve controlling the inlet port having a converging sleeve extending into the discharge port, and a valve on'the head of the piston having a stem movable in the sleeve, said stem having a passage operative to alternately communicate with the cylinder and the discharge port.

4. A fluid pressure producing device comprising a reservoir, 9. cylinder having an inlet port communicating with the reservoir and a discharge port, a piston reciprocable in the cylinder, a valve controlling the inlet port, a converging sleeve on the valve extending into the-discharge port, a valve on the head of the piston having a stem movable in the sleeve, a chamber in the valve, and a passage in the stem communicating with the chamber and alternately communicating with the cylinder and the discharge port.

5. A fluid pressure producing device comprising a reservoir, a cylinder having an inlet port communicating with the reservoir and a discharge port, apiston reciprocable in the cylinder, a valve controlling the inlet port, a converging sleeve on the valve extending into the discharge port, a valve on the head of the piston having a stem extending through the sleeve, a spring interposed between the valves, a chamber in the valve on the piston, and a passage in the stem of the valve communicating with the chamber and alternately communicating with the cylinder and the discharge port.

6. Afluid pressure producing device comprising a reservoir, a cylinder having an inlet port communicating with the reservoir, a head on the cylinder having an opening providing a discharge port for the cylinder, a piston reclprocable in the cylinder, a flexible cup on the head of the cylinder controlling the inlet port, a converging sleeve on the cup extending into the discharge port, a leak-proof cup on the head of the piston, a valve seated on the leak-proof cup, a stem for the valve extending through the sleeve, a spring interposed between the valves, a chamber in the valve on the leak-proof cup, and a passage in the stem of the valve communicating with the chamber and adaptable for alternate communication with the cylinder and the discharge port.

'7. A fluid pressure braking system comprising a reservoir, a cylinder having an inlet port communicating with the reservoir, a head on the cylinder having an opening providing a discharge port for the cylinder, a fluid pressure motor connected to the discharge port, a friction element actuated by the motor, a flexible cup on the head of the cylinder controlling the inlet port, a converging sleeve on the cup extending into the discharge port, a piston reciprocable in the cylinder, means for advancing the piston, a leak-proof cup on the head of the piston, a valve seated on the leak-proof cup, a stem on the valve extending through the sleeve, a chamber in the valve, and

a passage in the stem communicating with the 

